I have similar questions.
@Numo
Answer to Question 1 = No
Answer to Question 2 = No
@Michael
Answer to Question 1 = No, Artifact sets simply do the chance percentage shown regardless of ACC or RESIST
Answer to Question 2 = No, Frost set only works when the enemy attacks your hero.
In Summation,
Artifact gear sets bypass the ACC vs. RESIST game mechanic.
ACC & RESIST only apply to Hero Skills.
Proactive 4 Piece Artifact sets:
Reactive 4 Piece Artifact sets:
If you are trying to Crowd Control the enemy with a hero that does AOE, You should use one of the Proactive sets.
Stun, Taunt, or Daze are good C.C options to use when your hero is initiating the first attack on the enemy.
Frost, Retaliation, or Frenzy are good options to use when enemy heroes are initiating the first attack on your hero.